AMC7812SPAPR Datasheet, PDF (33/92 Pages) Texas Instruments – 12-Bit Analog Monitoring and Control Solution with Multichannel ADC, DACs, and Temperature Sensors

AMC7812
www.ti.com
SBAS513E – JANUARY 2011 – REVISED SEPTEMBER 2013
Handshaking with the Host (see AMC Configuration Register 0)
The DAV pin and the DAVF (data available flag) bit in AMC Configuration Register 0 provide handshaking with
the host. Pin and bit status depend on the conversion mode (direct or auto), as shown in Figure 84 and
Figure 85. In direct mode, after ADC-n-Data Registers of all of the selected channels are updated, the DAVF bit
in AMC Configuration Register 0 is set immediately to '1', and the DAV pin is active (low) to signify that new data
are available. Reading the ADC-n-Data Register or restarting via the external CNVT pin, the ADC clears the
DAVF bit to '0' and deactivates the DAV pin (high). If an internal convert start (ICONV bit) is used to start the new
ADC conversion, in order to reset the DAV status, an ADC-n-Data Register must be read after the current
conversion finishes before a new conversion can be started.
In auto-mode, after the ADC-n-Data Registers of the selected channels are updated, a pulse of 1µs (low)
appears on the DAV pin to signify that new data are available. However, the DAVF bit is always cleared to '0' in
auto-mode.
a) Internal Trigger, Direct Mode:
SS
Set ICONV
bit to ‘1’
First
Internal
Trigger
SDI
Read Data
DATA
Set ICONV
bit to ‘1’
Second
Internal
Trigger
Read Data
DATA
DAV
First Conversion of
the Channels Specified in
the ADC Channel Register
Second Conversion of
the Channels Specified in
the ADC Channel Register
b) Internal Trigger, Auto Mode:
SS
Set ICONV Internal
bit to ‘1’ Trigger
SDI
1ms
DAV
First Conversion of
Second Conversion
the Channels Specified in
the ADC Channel Register
Third Conversion
Figure 84. ADC Internal Trigger
a) External Trigger, Direct Mode:
CNVT
DAV
First
Trigger
First Conversion of
the Channels Specified in
the ADC Channel Register
Second
Trigger
Third
Trigger
Second Conversion of
the Channels Specified in
the ADC Channel Register
Third Conversion of
the Channels Specified in
the ADC Channel Register
b) External Trigger, Auto Mode:
CNVT
First
Trigger
1ms
DAV
First Conversion of
the Channels Specified in
the ADC Channel Register
Second Conversion of
the Channels Specified in
the ADC Channel Register
Third Conversion of
the Channels Specified in
the ADC Channel Register
Figure 85. ADC External Trigger
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